Free turbine pump

ABSTRACT

A free turbine pump for a well including: an axial flow turbine and an axial flow pump interconnected in axially aligned, end-toend relation with the turbine above the pump, the turbine having a power fluid intake adjacent its lower end and having a power fluid exhaust adjacent its upper end for spent power fluid, the pump having a well fluid inlet adjacent its lower end, and having a production fluid outlet adjacent its upper end and adjacent the power fluid intake; and means between the power fluid intake and the production fluid outlet for balancing axial thrust forces on the turbine and pump. This balancing means includes upperwardly and downwardly facing areas to which the production fluid pressure and the power fluid pressure are applied to achieve axial thrust balance.

United States Patent Brown et al.

' 11 3,847,512 [451 Nov. 12*, 1974 FREE TURBINE PUMP [75] Inventors: Francis Barton Brown, La

Crescenta; John W. Erickson, Huntington Beach, both of Calif.

[73] Assignce: Kobe Inc., Huntington Park, Calif.

22 Filed: Junel8, l973 [21] Appl. No.: 370,944

[52] US. Cl. 417/365, 417/408 [51] Int. Cl. F04b 17/00 [58] Field of Search 417/365, 408

[56] References Cited I UNITED STATES PATENTS 3,143,078 8/1964 Gaslow et al. 417/365 3,171,355 3/1965 Harris et al. 417/365 3,758,238 9/1973 Erickson et al 417/408 [57] ABSTRACT A free turbine pump for a well including: an axial flow turbine and an axialflow pump interconnected in axially aligned, end-to-end relation with the turbine above the pump, the turbine having a-power fluid intake adjacent its lower end and having a power fluid exhaust adjacent its upper end for spent power fluid, the pump having a well fluid inlet adjacent its lower end, and having a production fluid outlet adjacent its upper end and adjacent the power fluid intake; and means between the power fluid intake and the production fluid outlet for balancing axial thrust forces on the turbine and pump. This balancing means includes upperwardly and downwardly facing areas'to which the production fluid pressure and the power fluid pressure are applied to achieve axialthrust balance 8 Claims, 3 Drawing Figures P ATENIEB um 12 m4 3.847.51 2

sum 20? 2 I 1 FREE TURBINE PUMP CROSS REFERENCE TO RELATED APPLICATION This application is related to-our co-pending patent application Ser. No. 274,594, filed July 24, 1972, and having the same title, now Pat. No. 3,758,238 issued Sept. ll, 1973'.

BACKGROUND OF INVENTION The present invention relates in general to pumps and, more particularly, to fluid operated pumps for oil wells, or the like. Still more particularly, the invention contemplates a free turbine pump capable ofbeing ci'rculated into and out of the well hydraulically.

In general, the invention contemplates a free turbine pump which includes an axial flow turbine and an axial flow pump interconnected in axially aligned, end-toend relation with the turbine above the pump, the turbine having a power fluid intake and having a power fluid exhaust for spent power fluid, and thepumphaving a well fluid inlet and having a production fluid outlet.

In the free turbine pumpof our aforementionedcopending patent application, axial thrust balancing of the turbine and pump forces is achieved by locating the power fluid intake adjacent the upper end of theturbine and the power fluid exhaust adjacent the lower.

end thereof, and by locating the well fluid inlet adjacent the upper end of the pump and the production fluid outlet adjacent the lower end thereof. This arrangement of the power fluid intake, the'power'fluid exhaust, the well fluid-inlet, and the production fluid outlet, results in excellent'balancing of-theturbine and pump forces, the turbine producing a downward force The invention may be summarized as including, and an important object is to provide a free turbine pump I which includes: an axial flow turbine and an axial flow which will be evident to those skilled in the fre'eturbine.

and thepump an upward onewhich cancel each other.

However, the foregoing construction has one disadvantage, viz., locating the well-fluid inlet of the pump adjacent the upper end thereof results in relatively high losses because the fluid velocities are high and the passage means leading to the well fluid inlet arenecessarily relatively small because of the limited space available in the well.

OBJECTS AND SUMMARY OF INVENTION the upper end thereof, and adjacent thepower fluid intake.

With the foregoing arrangement, flow losses in the well fluid flowing to the well fluid inlet of the pump are minimized, which is an important feature of the invention.

Another and important object of the invention is to provide means between the power fluid intake and the production fluid outlet for balancing axial thrust forces on the turbine and the pump.

ing area and exposed to the pump interconnected in axially'aligned, end-to-end relation with the turbine above the pump, the turbine having a power fluid intake adjacent its lower end and having a power fluid exhaust adjacent its upper endfor spent power fluid, and the pump'having a well fluid inlet adjacent its lower end and having a production fluid outlet adjacent its upper end and adjacent the powerfluid intake; and means between the power fluid intake and the production fluid outlet for balancing axial thrust forces on the turbine and the pump.

Another object of importance is to provide such a balancing means comprising downwardly-facing and upwardly facing areas respectively exposed to the power fluid pressure and the production fluid pressure.

construction wherein the thrust balancing means also includes an upwardly facing, annular area connected to the shaft and spaced axiallyfrom'the downwardly facproduction fluid pressure in the production fluid outlet. J A v The foregoing objects, advantages, features and results of-the present invention, together with various other objects, advantages, features and results thereof pump art in the'light of this disclosure, may be achieved with the exemplary embodiment of the invention illustrated in the accompanying drawings and described in detail "hereinafter.

DESCRIPTION OF DRAWINGS In the drawings: j FIG. 1 is a semidiagrammatic vertical sectional view of the upper end of a free turbine pump of the invention in conjunction with a parallel, closed power fluid system; i

FIG. 2'is a downward continuation of FIG. 1; and

FIG. 3 is an enlarged, vertical sectional view showing an axial thrust balancing means of the invention.

DESCRIPTION or EXEMPLARY EMBODIMENT or INVENTION Referring initially to FIGS. 1 and 20f the drawings a bottom hole assembly 10 is suspended in an oil well casing llvby a power fluid tubing 12 the power fluid being, for example, clean crude oil. It will beunderstood that the-casing'll is provided with perforations, not shown, for admitting well fluid from the producing formation or formations into the casing.

The bottom hole assembly 10 provides'a chamber 14 for a'free turbine pump 16 of the invention. As will be explained in more detail hereinafter, the turbine pump 16 ishydrauically movable through the power tubing l2between the surface and an operating position inthe chamber '14. "When the turbine pump '16 is in its operat ing-position, it is seated on a standing valve 18 carried by the bottom hole assembly at the lower end of the pump chamber.

Paralleling the power tubing 12 and connected at their lower ends to the bottom hole assembly 10 are a spent power fluid return tubing and a production fluid tubing 22. These tubings respectively convey spent power fluid and production fluid from the well to the surface. The return and production tubings 20 and 22 respectively communicate with downward extension passages 23 and 24 in the bottom hole assembly 10.

The turbine pump 16 is run in hydraulically by inserting it into the upper end of the power tubing 12 at the surface and then introducing fluid into the power tubing above the pump. This displaces the pump 16 downwardly through the power tubing 12 into its operating position in the pump chamber 14, wherein the pump is seated on the standing valve 18. Fluid in the power tubing 12 below the pump 16 is displaced upwardly through the return and/or production passages 23 and 24 and tubings 20 and 22. When it is desired to circulate the pump 16 out of the well hydraulically, fluid under pressure is introduced into the upper end of the production tubing 22, the return tubing 20 being closed at its upper end. Such fluid enters the pump chamber 14 beneath the pump 16, through the production tubing extension passage 24, as will be clear from FIG. 2, and displaces the pump upwardly out of the pump chamber and upwardly through the power tubing 12. The pump 16 is provided at its upper end with the usual packer mandrel 26 carrying one or more packer cups 28 which prevent upward external bypassing of the pump 16 by the fluid used to circulate the pump upwardly out of the well.

The turbine pump 16 is provided adjacent its upper end with an axial flow turbine 30 and adjacent its lower end with an axial flow pump 32 arranged in end-to-end relation and interconnected by a common shaft 34.

The axial flow turbine 30 is provided with a power fluid intake 36 adjacent its lower end and a spent power fluid exhaust 38 adjacent its upper end. The power fluid intake 36 communicates with the power tubing 12 through ports 39 in the packer mandrel 26, an axial passage 40 in the packer mandrel, ports 41 in the packer mandrel, a passage 42 in the bottom hole assembly 10, an annular space 43 between the chamber 14 and the pump 16, and ports 57 in the pump. (A downwardly opening check valve 44 in the passage 40 prevents upward flow through this passage when circulating the pump 16 out of the well.) The power fluid exhaust 38 communicates with the return tubing extension passage 23 through an axial passage 45 in the pump 16 and ports 46 in the bottom hole assembly 10.

The axial flow pump 32 is provided with a well fluid inlet 48 adjacent its lower end which communicates directly with the standing valve 18. The pump 32 is provided with a production fluid outlet 50 at its upper end which communicates through ports 52 with an annular space 54 between the chamber 14 and the pump 16. This annular space communicates at its lower end with the lower end of the production tubing extension passage 24 through ports 56 in the bottom hole assembly 10.

Thus, the power fluid from the power tubing 12 enters the turbine 30 through its lower power fluid intake 36 and the spent power fluid discharged from the upper power fluid exhaust 38 enters the return tubing 20, all

by way of the ports and passages hereinbefore described. Similarly, the well fluid flowing through the standing valve 18 enters the lower well fluid inlet 48 of the pump 32 directly, and the production fluid discharged from the upper production fluid outlet 50 enters the production tubing 22, again by way of the ports and passages described.

Although the axial thrust forces of the turbine 30 and the pump 32 are balanced per se, there is net unbalance on the rotating system because the upper end 84 of the shaft 34, FIG. 1, and the lower end 86, FIG. 2, are exposed to unequal pressures causing a net downward thrust force. The invention provides means 60, FIG. 3, between the power fluid intake 36 and the production fluid outlet 50 for balancing such thrust force, which is an important feature.

More particularly, the axial thrust balancing means 60 of the invention includes an upwardly facing annular area 62 and a smaller, downwardly facing annular area 64 respectively exposed to the production and power fluid pressures and respectively formed on suitably interconnected members 66 and 68 connected to upper and lower portions of the shaft 34.

The annular area 62 is exposed to the production fluid pressure through an annular clearance 70 surrounding the member 66, an annular grove 72 surrounding the same member, and a longitudinal passage 74 in the pump 16 which communicates at its lower end with the production fluid outlet 50.

The area 64 communicates through a passage 76 in the pump 16, an annular grove 78 in the pump, and radial ports 80 and 82 in the pump, with the annular space 43 containing power fluid at the pressure obtaining in the power tubing 12.

Thus, the area 62 is exposed to the production fluid pressure and the area 64 is exposed to the power fluid pressure.

It will be noted that the upper end 84 of the shaft 34, FIG. 1, is exposed to the spent power fluid pressure in the exhaust 38, and that the lower end 86 of the shaft 34 is exposed to the pressure in the well fluid inlet 48. The areas 62 and 64 are so selected that the pressures acting thereon, and the pressures acting on the shaft ends 84 and 86, produce axial-thrust forces which are all balanced, or substantially balanced. Preferably, there is a slight net downward axial thrust force to eliminate any axial backlash of the shaft.

It will be noted that with the foregoing balancing means 60, the well fluid may enter the lower end of the pump 32 directly through the well fluid inlet 48, which is of large area. This minimizes flow losses, as hereinbefore explained.

While separate power fluid return and production tubings 20 and 22 are shown, it will be understood that either of these may be replaced by the casing 11 by installing a packer between the casing and the bottom hole assembly 10, in which case the casing becomes one of the tubing strings of the system.

Although an exemplary embodiment of the invention has been disclosed for purposes of illustration, it will be understood that various changes, modifications, and substitutions may be incorporated in such embodiment without departing from the invention as hereinafter claimed.

We claim as our invention:

1. In a turbine pump for a well, the combination of:

a. an axial flow turbine and an axial flow pump interconnected in axially aligned, end-to-end relation with said turbine above said pump;

b. said turbine having a power fluid intake adjacent its lower end, and having a power fluid exhaust adjacent its upper end for spent power fluid;

c. said pump having a well fluid inlet adjacent its lower end, and having a production fluid outlet adjacent its upper end and adjacent said power fluid intake; and

d. means between said power fluid intake and said production fluid outlet for balancing axial thrust forces on said turbine and said pump.

2. A turbine pump as set forth in claim 1 wherein said turbine and said pump are interconnected by a shaft the upper end of which is exposed to the spent power fluid pressure in said power fluid exhaust, said thrust balancing means including a downwardly facing, annular area connected to said shaft and exposed to the power fluid pressure in said power fluid intake.

3. A turbine pump according to claim 2 wherein said thrust balancing means also includes an upwardly facing, annular area connected to said shaft and spaced axially from said upwardly facing area and exposed to the production fluid pressure in said production fluid outlet.

4. In a fluid operated, free turbine pump system for a well, the combination of:

a. at least two tubings in the well;

b. a free. turbine pump of a size to be movable through one of said tubings between the surface and an operating position in the well;

c. said turbine pump comprising an axial flow turbine and an axial flow pump interconnected in axially aligned, end-to-end relation with said turbine above said pump;

d. said turbine having a power fluid intake adjacent its lower end and having a power-fluid exhaust adjacent its upper end for spent power fluid;

f. said pump having a well fluid inlet adjacent its lower end, and having a production fluid outlet adjacent its upper end and adjacent said power fluid intake;

g. means between said power fluid intake and said production fluid outlet for balancing axial thrust forces on said turbine and said pump;

h. one of said tubings being a'supply tubing for conveying power fluid under pressure downwardly in the well from the surface;

. said power fluid intake communicating with said supply tubing;

j. another of said tubings being a production tubing for conveying production fluid upwardly in the well to the surface;

k. said production fluid outlet communicating with said production tubing;

1. power fluid return means for, conveying spent power fluid upwardly in the well from said power fluid exhaust to the surface; and

111. said well fluid inlet communicating with the well.

5. A turbine pump as set forth in claim 4 wherein said turbine and said pump are interconnected by a shaft the upper end of which is exposed to the spent power fluid pressure in said power fluid exhaust, said thrust balancing means including a downwardly facing, annular area connected to said shaft and exposed to the power fluid pressure in said power fluid intake.

6. A turbine pump according to claim 5 wherein said thrust balancing means also includes an upwardly facing, annular area connected to said shaft and spaced axially from said upwardly facing area and exposed to the production fluid pressure in said production fluid outlet.

7. A free turbine pump system as defined in claim 6 wherein said power fluid return means is a third tubing set in the well.

8. In a turbine pump for a well, the combination of:

forces on said turbine and said pump.

* l =l l= 

1. In a turbine pump for a well, the combination of: a. an axial flow turbine and an axial flow pump interconnected in axially aligned, end-to-end relation with said turbine above said pump; b. said turbine having a power fluid intake adjacent its lower end, and having a power fluid exhaust adjacent its upper end for spent power fluid; c. said pump having a well fluid inlet adjacent its lower end, and having a production fluid outlet adjacent its upper end and adjacent said power fluid intake; and d. means between said power fluid intake and said production fluid outlet for balancing axial thrust forces on said turbine and said pump.
 2. A turbine pump as set forth in claim 1 wherein said turbine and said pump are interconnected by a shaft the upper end of which is exposed to the spent power fluid pressure in said power fluid exhaust, said thrust balancing means including a downwardly facing, annular area connected to said shaft and exposed to the power fluid pressure in said power fluid intake.
 3. A turbine pump according to claim 2 wherein said thrust balancing means also includes an upwardly facing, annular area connected to said shaft and spaced axially from said upwardly facing area and exposed to the production fluid pressure in said production fluid outlet.
 4. In a fluid operated, free turbine pump system for a well, the combination of: a. at least two tubings in the well; b. a free turbine pump of a size to be movable through one of said tubings between the surface and an operating position in the well; c. said turbine pump comprising an axial flow turbine and an axial flow pump interconnected in axially aligned, end-to-end relation with said turbine above said pump; d. said turbine having a power fluid intake adjacent its lower end and having a power fluid exhaust adjacent its upper end for spent power fluid; f. said pump having a well fluid inlet adjacent its lower end, and having a production fluid oUtlet adjacent its upper end and adjacent said power fluid intake; g. means between said power fluid intake and said production fluid outlet for balancing axial thrust forces on said turbine and said pump; h. one of said tubings being a supply tubing for conveying power fluid under pressure downwardly in the well from the surface; i. said power fluid intake communicating with said supply tubing; j. another of said tubings being a production tubing for conveying production fluid upwardly in the well to the surface; k. said production fluid outlet communicating with said production tubing; l. power fluid return means for conveying spent power fluid upwardly in the well from said power fluid exhaust to the surface; and m. said well fluid inlet communicating with the well.
 5. A turbine pump as set forth in claim 4 wherein said turbine and said pump are interconnected by a shaft the upper end of which is exposed to the spent power fluid pressure in said power fluid exhaust, said thrust balancing means including a downwardly facing, annular area connected to said shaft and exposed to the power fluid pressure in said power fluid intake.
 6. A turbine pump according to claim 5 wherein said thrust balancing means also includes an upwardly facing, annular area connected to said shaft and spaced axially from said upwardly facing area and exposed to the production fluid pressure in said production fluid outlet.
 7. A free turbine pump system as defined in claim 6 wherein said power fluid return means is a third tubing set in the well.
 8. In a turbine pump for a well, the combination of: a. an axial flow turbine and an axial flow pump interconnected in axially aligned, end-to-end relation with said turbine above said pump; b. said turbine having a power fluid intake adjacent its lower end, and having a power fluid exhaust adjacent its upper end for spent power fluid; c. said pump having a well fluid inlet adjacent its lower end, and having a production fluid outlet adjacent its upper end and adjacent said power fluid intake and d. fluid pressure responsive means connected to said turbine and said pump for balancing axial thrust forces on said turbine and said pump. 